Ceiling fan motors as induction generator


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Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 4817
Posted: 02:35am 08 Oct 2006      

I've read a few web sites about using induction motors as generators by connecting capacitors across the output.
http://www.qsl.net/ns8o/Induction_Generator.html
http://www.windpower.org/en/tour/wtrb/async.htm
http://www.microhydropower.com/staffpubs/staff4.htm
http://users.aber.ac.uk/iri/WIND/TECH/MISC/MotorsAsGenerator s.html
The problem with these is they are usually 4 or 2 pole motors, and need to be spun at over 1500 or 3000 RPM before they start generating. They can be tricked into working at lower speeds with changes to the capacitor value.
Now a ceiling fan has a much higher pole count, 8 or more, as its a slow turning induction motor. I wonder if it could be used as a low speed induction generator. It would need some smart electronics to...
   -Only apply load once up to speed.
   -adjust the capacitor value with RPM to maintain excitation.
   -disconnect load below a RPM to avoid demagnetising the rotor.
   - if the rotor is demagnetised, apply a brief pulse of power to the coils to magnetise the rotor.

The advantage is any cheap ceiling fan could be used as a generator without buying magnets and machining the rotor down to glue them in place. Bascially you get a old fan motor and attach the electronics to make a generator.

I dont know, what do you guys think?

Glenn

People say 2020 is a terrible year, with the bush fires, COVID 19, and riots. But I see it as the year we woke up to ourselves.

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